The U.S. Supreme Court broke with the past Tuesday and pushed for measures that will truly define the present. In a starkly divided 5-4 decision in Shelby County vs. Holder, the court ruled that the formula used to determine which states must receive “pre-clearance” before changing voting laws was outdated and unconstitutional.

This newspaper applauds the ruling. Parts of the landmark Voting Rights Act are based on data almost 50 years old — a practice that, we wrote June 3, “is unfair, bad policy and, possibly, unconstitutional.” That is precisely what the court found.

But let’s be clear: The court did not strike down the Voting Rights Act. Nor did it strike down Section 5, the part of the law that sets onerous pre-clearance requirements on states and local jurisdictions with histories of discriminatory practices. It ruled that Section 4, which defines the formula for who should be on the Section 5 list, is unconstitutional. Much of the formula was based on minority voter turnout and registration from the 1964 presidential election.

The court’s problem isn’t with the law; it’s with the outdated formula.

The challenge now is to update that formula. Section 5 is still a critical and necessary part of the Voting Rights Act, providing important protections to the integrity of our election system. So it is now incumbent on a highly partisan Congress to rewrite the rules. If lawmakers do nothing, it will effectively gut this critical voting rights law. The teeth of the act will lie only in Section 2, which allows victims of discriminatory voting practices to sue jurisdictions, after the fact. That would place unfair financial burdens on possible victims and offer relief often after an election has already been held.

Congress must embrace the court’s challenge and immediately begin setting procedures to construct a formula in an age where discrimination is more subtle and nuanced. As both the majority and dissenting opinions noted in Shelby, the concern today is no longer literacy tests but the dilution of minority representation through gerrymandering and at-large districts. We would add that another issue is the placement of voting impediments: the cutting of voting hours and days, as well as voter ID laws.

In order to tamp down the overt politicization that could threaten this effort as soon as it begins, Congress should consider forming a bipartisan commission (similar to ones that tackled base closings and deficit reduction) that would offer parameters for the new Section 4.

Whatever the route taken, precision, fairness and speed are critical. Already, states are using the Shelby ruling to enact laws that had previously been blocked by the Justice Department as discriminatory. Texas Attorney General Greg Abbott announced that the state’s voter ID law will take effect immediately, a decision this board laments.

While updating the formula guiding Section 5 is fair and necessary, this cannot be used as an excuse to allow it to die by neglect.

Lawmakers will be called on to show a type of leadership rarely seen since passage of the original Voting Rights Act.